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Photoinduced Charge Separation by Polymer-Bound Chromophores

Description: This project has examined the photodynamic behavior of water-soluble polymers that have covalently linked hydrophobic chromophores spaced along the chains. These polymeric systems have been examined for photoinduced charge separation with electron-accepting ions having different total charge. Focus has been on the excited singlet (S{sub 1}) state formed by laser flash absorption. The effects of pH and ionic strength -- factors that govern the conformational nature of the polymer in solution -- … more
Date: September 1, 1991
Creator: Rodgers, M. A. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Measurement of energy deposited by charged-particle beams in composite targets

Description: We have measured the energy deposited in two types of composite targets by a number of charged-particle beams: targets made of /sup 238/U, Lucite, and polyethylene were exposed to 0.26-GeV protons and 0.33-GeV deuterons, and aluminum-Lucite composites were exposed to 0.5-GeV electrons. In addition, we measured neutrons and gamma rays emitted from solid targets of various materials (including /sup 238/U and iron) exposed to 0.26-GeV protons and 0.33-GeV deuterons. We used passive detectors (ther… more
Date: July 2, 1980
Creator: Farley, E.; Becker, J.; Crase, K.; Howe, R. & Selway, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Multi-transducer dummy unit evaluation of polystyrene bead foam as an encapsulant for electronic packages

Description: A dummy electronic assembly without electronic components was used to measure loadings and deflections caused by 0.2, 0.3, 0.4, 0.5 and 0.6 g/cm/sup 3/ densities of polystyrene bead foam during fusion and thermal cycling. Previously developed and proven transducers showed that the lower three densities caused low and safe loads and deflections, but that the highest two densities must be used with care for fragile electronic components.
Date: September 1, 1980
Creator: Swanson, G. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A replaceable reflective film for solar concentrators

Description: The 3M Company manufactures a silvered acrylic film called ECP-305 that is regarded as the preferred reflective film for use on stretched-membrane heliostats. However, ECP-305 will degrade in time, due to both corrosion of the silver layer and delamination at the film's silver-to-acrylic interface, and will eventually need to be replaced. 3M uses a very aggressive adhesive on this film, and once it is laminated, replacement is very difficult. The purpose of this investigation was the developmen… more
Date: September 1, 1991
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Improved tunnel resistance of silvered-polymer mirrors

Description: This report documents the research performed at the Solar Energy Research Institute during fiscal year (FY) 1991 to develop ways to prevent delamination failure (known as tunneling) of silvered-polymer reflector materials. Several promising approaches have been identified and demonstrated that substantially reduce such failures. These approaches include (1) use of Tedlar edge tape rather than the manufacturer-recommended ECP-244 tape, (2) thermal treatment of laminated reflector/substrate const… more
Date: October 1, 1991
Creator: Jorgensen, G.; Schissel, P.; Kennedy, C.; Shinton, Y.; Powell, D. & Siebarth, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Removable foam encapsulants

Description: This paper describes the use of two different expandable bead foams as solvent removable encapsulants; specifically they are polystyrene (STYROPOR BF-414, BASF Wyandotte) and a styrenemaleic anhydride copolymer (DYTHERM X214, ARCO/Polymers). These expandable bead foams are commercially available and normally used in insulating applications. However, they have been adapted to the unusual task of encapsulating sophisticated and expensive electronic hardware which requires a rework capability. The… more
Date: January 1, 1982
Creator: Wischmann, K.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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DOE Task Force meeting on Electrical Breakdown of Insulating Ceramics in a High Radiation Field

Description: This volume contains the abstracts and presentation material from the Research Assistance Task Force Meeting Electrical Breakdown of Insulating Ceramics in a High-Radiation Field.'' The meeting was jointly sponsored by the Office of Basic Energy Sciences and the Office of Fusion Energy of the US Department of Energy in Vail, Colorado, May 28--June 1, 1991. The 26 participants represented expertise in fusion, radiation damage, electrical breakdown, ceramics, and semiconductor and electronic stru… more
Date: August 1, 1991
Creator: Green, P.H. (comp.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radiogenic gas accumulation in TRU waste storage drums

Description: A field experiment was conducted over a four-year time span to determine the effect of high-activity transuranic (TRU) waste on the atmosphere within TRU waste storage drums typical of those generated in Savannah River Plant operation. Routine gas composition analyses showed that a significant amount of hydrogen can accumulate in drums that contain high alpha activity, and that flammable gas mixtures could form in such drums in spite of the radiolytic consumption of oxygen. According to this st… more
Date: January 1, 1982
Creator: Ryan, J.P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Moisture penetration evaluation of polystyrene bead foam as an encapsulant for electronic packages

Description: Discs of polystyrene bead foam were used to measure resistance to high-pressure moisture penetration. Densities of 0.2, 0.3, 0.4, 0.5, and 0.6 g/cm/sup 3/ processed at various fusion times and temperatures were tested. Only three fusion conditions for 0.6 g/cm/sup 3/ density were impervious to moisture penetration at 1724 kPa for 24 hours or more.
Date: June 1, 1980
Creator: Swanson, G. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Selective emitter. Task II topical report for radiative-cooling materials

Description: The theoretical basis of the selective emitter is that, if a material emits only in the 8-13 micron interval, it will absorb only in the same interval. After a survey of several candidate materials, the silicon oxynitride system was found to have better optical properties than previously used materials as well as economic feasibility, and efforts to acquire a sample are described. Other promising materials are described: polyvinylidene fluoride (Tedlar), silicon monoxide, silicon dioxide, and s… more
Date: September 20, 1981
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Toward more accurate loss tangent measurements in reentrant cavities

Description: Karpova has described an absolute method for measurement of dielectric properties of a solid in a coaxial reentrant cavity. His cavity resonance equation yields very accurate results for dielectric constants. However, he presented only approximate expressions for the loss tangent. This report presents more exact expressions for that quantity and summarizes some experimental results.
Date: May 1, 1980
Creator: Moyer, R. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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The physical properties of microcellular composite foams

Description: Recently we reported on a method of preparing microcellular composite foams. In this procedure an open-celled polystyrene foam is prepared by the polymerization of a high-internal-phase water-in-oil emulsion containing styrene, divinylbenzene, surfactant, free-radial initiator and water. After drying, the cells of the polystyrene foam are then filled with other materials such as aerogel or resoles. The physical properties of these materials, e.g., surface area, density, thermal conductivity, an… more
Date: January 1, 1989
Creator: Nyitray, A.M.; Williams, J.M.; Onn, D.; Witek, A. (Los Alamos National Lab., NM (USA) & Delaware Univ., Newark, DE (USA). Applied Thermal Physics Lab.)
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Application Experience and Field Performance of Silvered Polymer Reflectors

Description: The solar-weighted hemispheric reflectance of unweathered silvered acrylic mirrors exceeds 92%, and specular reflectance into a 4- milliradian, full-cone acceptance angle is greater than 90%. Comparison of outdoor and accelerated tests suggests that the protected silver can resist corrosion for the five-year life that is the current goal. An installation of parabolic troughs has been cleaned monthly for two years, and reflectance is regularly returned to within a few percent of the initial refl… more
Date: April 1, 1991
Creator: Schissel, P.; Jorgensen, G. & Pitts, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Alternate materials of construction for geothermal applications. Progress report No. 13, April--June 1977

Description: A program to determine if non-metallic materials such as polymers, concrete polymer composites, and refractory cements can be utilized as materials of construction in geothermal processes is in progress. To date, several high temperature polymer concrete systems have been formulated, laboratory and field tests performed in brine, flashing brine, and steam at temperatures up to 260/sup 0/C, and economic studies started. Laboratory data for exposure times greater than 2 years are available. Resul… more
Date: June 1, 1977
Creator: Steinberg, M. & Kukacka, L. E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Development of non-cellulosic insulation for transformers. Quarterly report No. 3, July 1980. General Electric No. CCR-80-16

Description: Work is nearly completed on an analytical model to demonstrate the advantages in both materials and losses to be gained by the utilization of thin insulation in transformers. Strip coating studies are under way. The measurement of the physical properties of film is completed and the measurement of electrical properties is nearing completion. The aging and compatibility studies are continuing.
Date: January 1, 1980
Creator: Fessler, W.A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Polarizability of the low frequency excitations in disordered solids. [Polymethylmethacrylate]

Description: An attempt to find manifestations of an electric dipole moment associated with the low-temperature thermal properties of glasses has enabled the setting of very low limits for GeO/sub 2/ and PMMA, 0.06 and 0.16 Debye respectively. Measurements of the temperature dependence of the dielectric constant and the electric field dependence of the thermal conductivity of SiO/sub 2/ in conjunction with dielectric measurements by Schickfus et al. has pinned down some of the features of a tunneling system… more
Date: October 1, 1975
Creator: Stephens, R. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Light-induced electron transfer vs. energy transfer in molecular thin-film systems

Description: Quenching of fluoranthene (FA) singlets by tetrabromo-o-benzoquinone (TBBQ) and N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) was studied both in xylene solutions and in spin-cast polystyrene (PS) films. Emphasis was placed on time-resolved fluorescence transients resulting from pulsed excitation. Linear Stern-Volmer plots were obtained for quenching in solution and gave diffusion-controlled rate constants, of 1.45 x 10/sup 10/ M/sup -1/ sec/sup -1/ and 1.53 x 10/sup 10/ M/sup -1/ sec/sup -1/… more
Date: January 1, 1980
Creator: Renschler, C. L. & Faulkner, L. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design options for low-conductivity window frames

Description: The window industry's commercialization of low-emissivity coatings and low-conductivity gas-filling over the past few years has helped to drastically reduce heat transfer rates through the glazed areas of windows. However, few changes have taken place in the design and construction of window frames and edges, leaving these elements to account for most of the heat transfer through today's state-of-the-art windows. This paper presents design and material requirements for the manufacture of low-co… more
Date: October 1, 1990
Creator: Byars, N. & Arasteh, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Simple home-made sensors for potentiometric titrations. [Nitroform CH(NO/sub 2/)/sub 3/]

Description: A sensor for potentiometric titrations was prepared by coating a spectroscopic graphite rod with a solution of poly(vinyl chloride) and dioctyphthalate in tetrahydrofuran. The reference electrode was an Ag/AgCl single-junction electrode. The sensor was used in precipitation, acid-base, compleximetric, and redox titrations. Preparation of the coated-graphite sensor is simple and rapid. Moreover, it is quite inexpensive. A limitation is its applicability in aqueous media only, because organic sol… more
Date: April 1, 1982
Creator: Selig, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hydrodynamic particle migration in small-amplitude, oscillatory, circular couette flow: The limits of reversibility

Description: Initially well-mixed suspensions of large spherical particles in viscous Newtonian fluids subjected to continuous nonhomogeneous shear flows demix and establish large concentration gradients. A number of experimental studies have determined that the particles migrate to the low shear-rate region in one-dimensional flow fields. Other investigators have proposed mechanisms to model the migration caused by the presence of nonuniform shear gradients. Here, we report on the shear-induced migration o… more
Date: January 1, 1992
Creator: Brenner, H. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Chemical Engineering); Altobelli, S. A. (Lovelace Medical Foundation, Albuquerque, NM (United States)); Graham, A. L.; Abbott, J. R. (Los Alamos National Lab., NM (United States)) & Monday, L. A. (Sandia National Labs., Albuquerque, NM (United States))
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Segmental interpenetration at polymer interfaces

Description: During the first year of this proposal significant strides have been made in understanding the nature of the interface in symmetric, diblock copolymers and the nature of the interface formed between immiscible homopolymers. Emphasis has been placed on the symmetric, diblock copolymers of polystyrene (PS) and polymethylmethacrylate (PMMA) since these diblock copolymers and the corresponding homopolymers are available over a wide range of molecular weight with narrow molecular weight distribution… more
Date: January 1, 1989
Creator: Russell, T. P. & Fleming, W. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Biological and clinical dosimetry. Progress report, October 1, 1980-September 30, 1981

Description: A second measurement of the event size distribution for 20 MeV neutrons was carried out at Ohio University to determine the reproducability of results. Again a significant difference between measurement and theoretical calculations by Caswell and Coyne was found. The measured fraction of events due to alpha particles was significantly lower than that predicted by the calculation of Casell and Coyne. Furthermore, the discrepancies with the theoretical calculations made by Caswell and Coyne were … more
Date: September 30, 1981
Creator: Laughlin, J. S. & Zeitz, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Design, analysis, and test verification of advanced encapsulation systems. Triannual report for period ending 31 July 1981

Description: The construction of optical and electrical verification test coupons of encapsulated solar cells and potted copper is detailed. Testing of these coupons was completed and the results are presented. Additionally, a thermal simulation of roof mounted array conditions was done and the results documented.
Date: November 1, 1981
Creator: Garcia, A. & Minning, C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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